Infusion sets are typically used to transfer fluids from a source to a patient. An infusion set typically includes a cannula assembly that may be made up of a cannula which is inserted into a patient with the use of a needle, and a cannula body which is used to hold the upstream end of the cannula. The needle is typically removed before fluid may be transferred through the cannula. The cannula body may be used to secure the cannula to a patient's body in a specific position. The cannula is attached to a tube, usually a flexible tube, which conducts fluid from a source to be transferred to the body.
Infusion sets may present a number of user-oriented, operational problems due to the competing interests of providing a device capable of being used by many, while being tailored to an individual's needs.
In one aspect of infusion sets, the length of a tube used in an infusion set must be able to reach a distance between the insertion site of the cannula and the source of the infused fluid. The tubes are typically flexible, allowing for convenience in handling by users. In the instance when a source is a portable source that may be worn by a patient, the length of tube necessary depends upon the relative positions of the source and the insertion site, which may be a function of the size of the patient. As well, patients may wish to alter the position where they wear the source and/or the insertion site depending upon individual circumstances. Tube suppliers manufacture various lengths of tubes. However, requiring patients to purchase various lengths of tubing depending upon their needs, and requiring suppliers to stock every length of tubing desired may be impractical. Patients who use tubes that are too long may insure that an adequate length is available, but risk entangling the excess tube in stray objects or potentially dislodging the cannula assembly or fluid source if the excess tubing snags.
In general, a need exists to improve the design of infusion sets to address this problem.